Physiologically-Based Signal Processing System and Method

Abstract

A system and method for improving sound quality for subjects with impaired hearing by applying a lowpass filter and a set of mid- to high-frequency narrowband filters to a signal. A set of narrowband filters are applied to sounds so that the impaired ear is stimulated to respond in a manner more similar to that of a healthy ear at low to moderate sound levels, for which intelligibility is high. Information falling outside of the set of narrowband filters is “discarded” or filtered out, which preserves the representation of the information in the narrowbands. Because energy at frequencies between the narrowband filters is discarded, the sound spectrum is significantly changed, resulting in a clearer sound that is more natural and higher in intelligibility than conventional sounds or sound processing techniques.

1 . A method for processing a sound spectrum, comprising the steps of: 
 low pass filtering said sound spectrum at a predetermined cutoff frequency; and    bandpass filtering said sound spectrum at a plurality of base frequencies above said predetermined cutoff frequency.    
     
     
         2 . The method of  claim 1 , wherein said base frequencies are sufficiently separated from each other to create bands of rejected frequencies alternating with bands of allowed frequencies.  
     
     
         3 . The method of  claim 2 , wherein said predetermined cutoff frequency is 1500 Hz.  
     
     
         4 . The method of  claim 3 , wherein said low pass filters and said bank of narrowband filters comprise linear filters.  
     
     
         5 . A system for processing a sound spectrum, comprising: 
 a low pass filter having a cutoff frequency; and    a bank of narrowband filters having base frequencies above said cutoff frequency.    
     
     
         6 . The system of  claim 5 , wherein said center frequencies are selected to create alternating bands of rejected frequencies and allowed frequencies above said cut-off frequency.  
     
     
         7 . The system of  claim 6 , wherein said predetermined cutoff frequency is 1500 Hz.  
     
     
         8 . The system of  claim 7 , wherein said low pass filter and said bank of narrowband filters are linear filter.  
     
     
         9 . A system for processing a sound spectrum, comprising: 
 means for filtering said sound spectrum to allow low frequencies to pass; and    means for filtering said sound spectrum to allow bands of higher frequencies to pass.    
     
     
         10 . The system of  claim 9 , wherein said means for filtering said sound spectrum to allow low frequencies to pass allow frequencies below about 1500 Hz to pass.  
     
     
         11 . The system of  claim 10 , wherein said bands of higher frequencies are interspersed with bands of frequencies that are rejected.